Coated substrate bodies for use as cutting elements are basically known.
Thus, for example in German Patent Document 100 17 909 A1, substrate bodies on a tungsten carbide basis and provided with a hard coating are known which have a titanum composite layer with at least one coating of TiC, TiN, TiCN, TiCO and TiCNO and an Al2O3 and/or Al2O3—ZrO2 composite layer. In the last mentioned case, ZrO2 particles are dispersed in an Al2O3 phase.
Furthermore, it is also known to provide layer sequences in the form of TiN—TiCN—TiN layers, optionally with an additional outer Al2O3 layer. Al2O3 layers which are deposited by means of a CVD process can, depending upon the process conditions, be in the form of α-Al2O3, κ-N2O3 or amorphous Al2O3. The German Patent Document DE 100 17 909 A1 discloses for the production of a TiCN layer, a CVD process in which at an average temperature range between 700° C. and 950° C., a reaction gas mixture is used which contains CH3CN.